Pressure vessels that are used in processing semiconductor wafers require constant access to the interior of the vessel or chamber. This constant access to the chamber poses quite a challenge in opening and closing technology. In processing a semiconductor wafer, the chamber of the vessel must be accessed for inputting the wafer and then accessed again for removing the wafer. This process may be repeated every few minutes, possibly 24 hours a day, 7 days a week. Therefore, speed as well as normal wear and tear become key concerns in the process.
Many technologies exist for opening and closing the door to the vessel. However, many of these technologies have drawbacks, because they attempt to use brute external force to hold the door mechanism and the vessel together. For instance, the typical multibolted flange configured to seal the chamber of the vessel is not practical from a time standpoint, because the repeated opening and closing of the flange overall takes a significant amount of time. In addition, the multibolted flange is impractical from a wear and tear perspective, because the repeated opening and closing of the flange wears down the bolts and nuts over time. Further, multibolted flanges utilize an external force to secure the flange to the vessel to the seal the vessel. This requires additional equipment and powering means to accomplish the overall task of processing the wafer. Other technologies to open and close the pressurized vessel and provide a seal to the chamber are known in the art and are not discussed here further.
What is needed is a method and apparatus for sealing a pressure vessel, whereby the apparatus takes advantage of the internal pressure of the vessel itself as a means to secure and seal the vessel.